Theodolite app compass no longer works in IPhone 6s

Really enjoyed this app with iPhone 5 however, after updating to IPhone 6S the compass is always reading north in any observed direction. All of my other installed Apps show the correct observed direction and are working correctly.
Appears not to be calibrated, although all of the indicators, green radio knobs, indicate that it is.... Hopefully there is a quick fix!!!!

The win about Theodolite, v5.0